As a rust preventing method and a rust preventing cover for a disk brake of an automobile, in Japanese Patent Application Laid-Open Publication No. 2003-267001, a rust preventing method and a rust preventing cover have been disclosed in which, after a tire assembly obtained by assembling a tire to an aluminum wheel is attached to a hub of an axle, a cover member covering the aluminum wheel is pasted to a side surface of the tire assembly via a peelable adhesive layer. This is a rust preventing method and a rust preventing cover in which, as a rust preventing cover for a disk brake of an automobile, a rust preventing cover including a cover member attached to a side surface of a tire assembly and covering the wheel and an adhesive section for peelably pasting the cover member to the side surface of the tire assembly is used. When an aluminum wheel is covered with such a cover member, intrusion of rain water, outdoor air containing salt content, and the like into a disk brake side through an opening is prevented. The cover member is pasted to the side surface of the tire assembly by the peelable adhesive layer. Therefore, workability is improved and a work time is substantially reduced. Since the cover member can be easily peeled, it is possible to collect the cover member without troubles. Further, when several hundred sheets of the cover members are supplied to an assembly line in a laminated state and peeled one by one and pasted to a side surface of a tire, stains on the adhesive layer can be prevented immediately before the pasting. Therefore, it is possible to prevent a pasting failure due to the stains. Packaging and management are facilitated (Japanese Patent Application Laid-Open Publication No. 2003-267001, paragraph 0026, FIG. 2).